For ChIP-seq, chromatin from 1% formaldehyde-fixed cells were fragmented to 200-500 bps by sonication for 5-6 mins using the Branson sonifer SFX250 ChIP-seq: Sequencing libraries were prepared with 1-5 ng of ChIP DNA samples and input sample using the Ovation Ultralow System V2 kit (Nugen). Libraries were sequenced with single-end (SE) 50-75 cycles on an Illumina Nextseq 500 Illumina genome analyzer